Hardware Implementation of a Novel Sliding Mode Controller for Photovoltaic Water Pumping Systems Without Energy Storage

this paper proposes a performance improvement of water pumping photovoltaic system based on an induction motor drive. The first contribution of this work consists in introducing an Integral Sliding Mode Speed Controller (ISMSC) to the Direct Torque Control (DTC) of the induction motor, in order to enhance the speed regulation loop and increase the system robustness against the motor parameters variation and the sudden variation of the irradiation. The second contribution is to implement the proposed DTC-ISMSC on an FPGA board in order to reduce the sampling period of the system and the delays in the control loop. Moreover, the extract of the maximum power is performed through the Perturb and Observe (P&O) technique. Finally, the performance of the photovoltaic pumping system controlled by the proposed DTC-ISMSC and P&O is demonstrated by digital simulation using Xilinx system generator tool. The ISMSC is compared also with a proportional integral controller. The obtained results have shown the better dynamic performance of the proposed DTC-ISMSC and P&O.